stocker programs, feedlot performance and carcass merit jim oltjen university of california, davis...
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Stocker Programs, Feedlot Stocker Programs, Feedlot Performance and Carcass MeritPerformance and Carcass Merit
Jim OltjenUniversity of California, Davis
April 10, 2008
UC Sierra Foothills Research & Extension Center
UC Davis Feedlot
OutlineOutline• Compensatory growth • Using Davis Growth Model for performance and carcass traits• Growing phase feed quality effects• Growing phase length effects• Previous nutrition effects on carcass merit and maintenance• Physiology of growth and fat development• Latest Research on:
– Patterns of marbling– Length of stocker phase effects on fat distribution– Length of stocker phase effects on rate of marbling and subQ fat gain– Residual feed intake relationship with maintenance requirements
• New model to predict fat distribution
Compensatory growth in beef cattleCompensatory growth in beef cattle
200
250
300
350
400
450
500
0 50 100 150 200 250 300
Days on feed
Em
pty
body
wt,
kg
CA-CACL-CACL-CLFA-CAFA-CL
From: Sainz et al., 1995
Sainz et al., 1995
Compensatory gain in feedlot steersCompensatory gain in feedlot steers
Sainz et al., 1995
Compensatory gain in feedlot steersCompensatory gain in feedlot steers
Sainz et al., 1995
Compensatory gain in feedlot steersCompensatory gain in feedlot steers
Davis Growth ModelDavis Growth Model
Net energy
Protein
Maintenance Fat (kg)TtrtrttrRtrttr
r
Davis Growth Model (Oltjen et al. 1986)Davis Growth Model (Oltjen et al. 1986)
DNABody
fatBody
ProteinBody
accretionDNA
accretionFat
SynthesisProtein nDegradatioProteinMetabolizable Energy Intake
Heat production
Biological processes: Biological processes: Cell proliferation and hypertrophyCell proliferation and hypertrophy
Homeorrhetic controlHomeorrhetic control
Biological processes: Biological processes: Synthesis and degradationSynthesis and degradation
Biological processes: Biological processes: maintenancemaintenance
Efficiency of conversion into net energy is related to both quantity and concentration of metabolizable energy in the diet
Effect of diet quality in growing phase to a constant BW endpoint
(327 kg)
Stocker cattle’s rate of gain is linear from 2 to 3 Mcal ME/kg DM
assuming cattle are fed ad libitum or have adequate available forage.
(growing phase to 327 kg BW)
Finishing daily gain is inversely and nearly linearly related to previous growing phase performance.
This hardly varied whether cattle were fed to equal body weight or fat content endpoints.
(growing phase to 327 kg BW)
Steers fed to an equal body weight endpoint were more sensitive to previous growing phase ration energy compared to steers fed to a constant fat endpoint.
Those fed higher energy diets as calves reached acceptable carcass fatness at much lighter weights.
Effect of growing phase length(MEC = 1.87 Mcal/kg)
(growing phase MEC 1.87 Mcal/kg)
Finishing period performance
(growing phase MEC 1.87 Mcal/kg)
Finishing period performance
(growing phase MEC 1.87 Mcal/kg)
Steers fed to an equal body weight endpoint were more sensitive to the length of the growing period compared to a constant fat endpoint.
Calf fed’s Calf fed’s reach carcass reach carcass fatness before fatness before desirable desirable slaughter slaughter weights, weights, confirming confirming previous work previous work that medium or that medium or small frame small frame steers require steers require a growing a growing period before period before slaughter, slaughter, particularly if particularly if
not implanted.not implanted.
Calf fed’s Calf fed’s reach carcass reach carcass fatness before fatness before desirable desirable slaughter slaughter weights, weights, confirming confirming previous work previous work that medium or that medium or small frame small frame steers require steers require a growing a growing period before period before slaughter, slaughter, particularly if particularly if
not implanted.not implanted.
Conversely, if we use longer growing Conversely, if we use longer growing periods due to increased cost of grain, periods due to increased cost of grain, cattle will have to be fed to larger weights cattle will have to be fed to larger weights for acceptable fatness, further for acceptable fatness, further exacerbating the progressive trend to exacerbating the progressive trend to larger carcasses in the industry.larger carcasses in the industry.
Intermuscular Fat Subcutaneous Fat Intramuscular Fat
Compensatory growth in beef cattleCompensatory growth in beef cattle
0
5
10
15
20
25
30
Carcass fat, % Backfat, mm Abdominal fat, kg
CA-CA CL-CA CL-CL FA-CA FA-CLFrom: Sainz et al., 1995
aa
a
b b
a ab
c cb
ab
a a
b
Compensatory growth in beef cattleCompensatory growth in beef cattle
0
2
4
6
8
10
KPH, % Marbling score Slight=7,Small=10
% LD fat
CA-CA CL-CA CL-CL FA-CA FA-CL From: Sainz et al., 1995
a
aba
ab
babab
a
b
b
ab ab ab
b
Sainz et al., 1995
Compensatory gain in feedlot steersCompensatory gain in feedlot steers
Sainz et al., 1995
Compensatory gain in feedlot steersCompensatory gain in feedlot steers
Sainz et al., 1995
Compensatory gain in feedlot steersCompensatory gain in feedlot steers
SEM
a
bb
Growth curves Growth curves
0
100
200
300
400
500
0 5 10 15 20 25 30 35
Age, months
Bod
y w
t, kg
Allometric growthAllometric growth
0
20
40
60
80
100
0 50 100 150 200 250 300
Carcass wt, kg
Wt,
kg
Muscle
Fat
Bone
Frame score and total body fatFrame score and total body fat
Growth gradients among adipose depots Growth gradients among adipose depots
Perirenal
Intermuscular Intramuscular
Subcutaneous
From: Bruns et al. (2004) J. Anim. Sci. 82:1315-1322
UC Sierra Foothills Research & Extension Center
From: Sainz & Vernazza-Paganini, 2004
From: Sainz & Vernazza-Paganini, 2004
From: Sainz & Vernazza-Paganini, 2004
UC Sierra Foothills Research & Extension Center
Gain in 12Gain in 12thth rib fat gain (BF. µm/day) in high and low growth rib fat gain (BF. µm/day) in high and low growth cattle backgrounded at two ME levelscattle backgrounded at two ME levels
Gain in intramuscular fat gain (IMF. %/day) in high and low Gain in intramuscular fat gain (IMF. %/day) in high and low growth cattle backgrounded at two ME levelsgrowth cattle backgrounded at two ME levels
UC Davis Feedlot
Residual Feed Intake• More efficient steers with negative RFI ate less (12%). • RFI was related to maintenance energy requirements
(r=0.42). • No ‘significant’ association with carcass traits. • Myofibrillar protein degradation rates were positively
related to maintenance energy requirements (r=0.76), but were not related to RFI (r=-0.14).
A genetic trait related to RFI should be used in prediction models to account for differences in maintenance.
Eventually adjust for protein synthesis/degration rate differences which are explicitly represented in the Davis Growth Model.
Intermuscular Fat Subcutaneous Fat Intramuscular Fat
Net energy
Protein
Maintenance Fat
Visceral(kg)
Sub(kg)
Intra(kg)
Inter(kg)
12/13th
Rib fat(mm)
Carcasscharacteristics
Davis Growth Model
KPH(kg)
KPH(%)
IMF(%)
First order differential equation
FatdtdS
s
Example: Subcutaneous fat (S; kg)
Constraint 14
1jj
Where j = 1 to 4 for each fat depot
d
dt
a proportional variable is a function of DNA and maximum
adipocyte size
s
Cell number (hyperplasia) ~ DNA
Cell size (hypertrophy) ~ maximum adipocyte size
Proportion of total fate.g. subcutaneous (S; kg) proportional fat
variable
14
1jkFatj
4
1jj
ADSMAX*DNAS
1DNA*kFats
ss
s
Constraint
ADSMAX – Maximum adipocyte size = 4.5 x 105 kg TG/kg DNA
Days on feed
Proportion )( of total body fat
Subcutaneous
Visceral
Intramuscular
Intermuscular
Grid of fat depot parameter values
Breedtype
Implanted n kFs kFm kFv
1 No 5 0.3 0.4 0.2
2 No 29 0.1 0.4 0.0
3 No 9 0.2 0.3 0.1
1 Yes 24 0.2 0.3 0.1
2 Yes 70 0.2 0.4 0.1
3 Yes 2 0.3 0.4 0.1
Grid of fat depot parameter valuesBreedtype
Implanted n kFs kFm kFv
1 No 5 0.3 0.4 0.2
2 No 29 0.1 0.4 0.0
3 No 9 0.2 0.3 0.1
1 Yes 24 0.2 0.3 0.1
2 Yes 70 0.2 0.4 0.1
3 Yes 2 0.3 0.4 0.1
Growth of four body fat depotsGrowth of four body fat depots
0
20
40
60
80
100
120
0 200 400 600 800
Age, d
Wei
gh
t, k
g
Intermuscular
Subcutaneous
Visceral
Intramuscular
Model Summary
• Good starting point for predicting–12/13th rib fat (mm), IMF (%), and KPH
(%) for breed type and implant status• More data is required to develop fat
depot parameters e.g. serial slaughter data. But data is scarce!
• Model needs to be evaluated
12/13th ribfat, mm
Su
bcu
tan
eo
us
fat,
kg
0 10 20 30 40 50 60
02
04
06
08
01
00
Frame size = Small (< 4)Frame size = Medium (>= 4 & <7)3.70 + 1.86 x ribfat (SE = 9.11)
Obs
erve
d s
ubcu
taen
ous
fat,
kg
0
10
20
30
40
50 (a)
0 10 20 30 40 50
-10
-5
0
5
10
Predicted subcutaneous fat, kg
Obs
erve
d -
pred
icte
d, k
g
(b)
From: Garcia et al., 2007
Body protein
Angus-Hereford steers
Salers heifers
Charolais bulls
DGM INRA
From: Garcia et al., 2007
Angus-Hereford steers
Salers heifers
Charolais bulls
Body fat
DGM INRA
Ingredient¹ Low Moderate Finishing
Chopped Oat Hay² 75.0 50.0 5.0
Chopped Alfalfa Hay ----- ----- 5.0
Steam-Flaked Corn³ 15.0 40.0 80.0
Yellow Grease 3.0 3.0 2.5
Molasses 2.0 2.0 4.0
Trace Mineral Salt 2.0 2.0 0.5
Oyster Shell Flour 1.0 1.0 0.5
Monosodium-Phosphate 1.0 0.75 -----
Sodium- Bicarbonate ----- ----- 1.25
Ammonium- Chloride ----- ----- 0.25
Potassium- Chloride ----- ----- 1.0
Urea (45% N) 1.0 1.25 1.0
Rumensin ----- ----- Per label
Formulated Values
DM % 73 80 80
NEm. Mcal/kg DM 1.32 1.59 2.22
Crude Protein.%DM 11.06 11.06 14.75
Composition of growth and finishing dietsComposition of growth and finishing diets
Weight gains in high (BX) and low (GX) growth cattle Weight gains in high (BX) and low (GX) growth cattle backgrounded at two ME levelsbackgrounded at two ME levels
200
250
300
350
400
450
500
550
600
250 300 350 400 450 500 550 600 650
Age, d
Bod
y w
t, k
g
BX-Low
BX-Moderate
GX-Low
GX-Moderate
1 2 3
The arrows show the beginning of the finishing phase for the BX-M (1). GX-M and BX-L (2) and GX-L (3) groups.
High growth Low growth P Values¹
Measurement² Low Moderate Low Moderate SEM³ Genotype Group
Hot carcass wt, kg 325.0 320.4 365.6 349.2 9.38 0.006 0.294
Ribeye area, cm² 74.91 73.77 84.26 78.14 3.30 0.071 0.303
Backfat,mm 12.46 13.34 12.71 12.81 0.495 0.789 0.354
KPH³. fat % 1.16 1.57 1.82 1.87 0.230 0.071 0.343
Marbling score 4 3.77 3.96 3.80 3.65 0.207 0.529 0.913
Quality grade 5 6.34 6.63 6.38 6.30 0.249 0.564 0.689
Yield grade 2.97 3.16 3.00 3.18 0.152 0.848 0.253
Backgrounding effects: carcass traitsBackgrounding effects: carcass traits
1 Probability of a Type 1 error2 Standard error of the mean (n=3/group)3 Kidney.pelvic and heart fat4 Marbling Score: ; 3 = Small 0; 4 = Modest 0.5 Quality Grade: 0-2=Standard; 3-5=Select; 6-8= Choice; 9-11= Prime
Compensatory growth in beef cattleCompensatory growth in beef cattle
100
200
300
400
500
600
700
800
1.0 1.2 1.4 1.6 1.8 2.0
Empty body wt gain, kg/day
Gai
n, g
/day
From: Sainz et al., 1995
Fat
Protein
Compensatory growth in beef cattleCompensatory growth in beef cattle
3
6
9
12
15
1.0 1.2 1.4 1.6 1.8 2.0
Empty body wt gain, kg/day
Bac
kfat
, mm
From: Sainz et al., 1995
CL-CA
Compensatory growth in beef cattleCompensatory growth in beef cattle
6.5
7.0
7.5
8.0
8.5
9.0
9.5
1 1.2 1.4 1.6 1.8 2
Empty body wt gain, kg/day
Mar
blin
g sc
ore
From: Sainz et al., 1995
Slight = 7-9, Small = 10-12
(growing phase to 327 kg BW)
Backfat, mm
Growing MEC, Mcal/kg
BW 1.87 3.06 3.06 limited MEI237 1.0 1.0 1.0
327 2.0 6.1 3.3
481 9.9 12.6 11.6
Growing phase to 327 kg BW
Marbling Score1
Growing MEC, Mcal/kg
BW 1.87 3.06 3.06 limited MEI237 0.9 0.9 0.9
327 2.6 5.2 3.7
481 8.7 8.0 8.9
Growing phase to 327 kg BW
10, devoid; 1, practically devoid0; 2, practically devoid50 3, practically devoid100; 4, traces0; 5, traces50; 6, traces100; 7, slight0; 8, slight50; 9, slight100
Table 1. Growth performance of finishing steers previously fed a forage diet (1.87 Mcal ME/kg DM) ad libitum (FA) or a high concentrate diet (3.06 Mcal ME/kg DM) at intake levels (CL) to achieve similar growing phase gains (Sainz et al., 1995).
CL FA
------------------------------------------------------------------------------------------------------------------
Period length, d 89 111
Intake, kg DM/d 10.98 11.73
Gain, kg/d 2.01 1.82
Feed/Gain 5.47 6.45
Viscera, kg 28.8 32.8
Relative maintenance BW-.75 .83 1.21
Residual feed intake, kg/d -.63 1.05
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What about limit feeding concentrate in growing period?